381-407－Structural evolution of the Northern Tyrrhenian Sea from new seismic data.pdf

Marine and Petroleum Geology 05 "0888# 270Ð396
Structural evolution of the Northern Tyrrhenian Sea from new
seismic data
A[ Mau}ret\ I[ i\ C[
Departement de Geotectonique\ CNRS!ESA 6961\ Universite Pierre et Marie Curie\ Case 018\ 64141\ Paris\ Cedex 94\ France
Received 02 September 0887^ received in revised form 10 January 0888^ accepted 09 February 0888
Abstract
We present the results of the deep rating LISA seismic survey supplemented by several industrial oil surveys[ The LISA
cruise shows the deep part of the crust and the Moho re~ections are seen at 6[4Ð7 s TWTT on several seismic lines on the Tuscan
"eastern# margin of the North Tyrrhenian Sea[ The Moho depth has been previously evaluated by refraction data at about 11Ð14 km
and this depth corresponds to the re~ections observed on our seismic pro_les[ Two kinds of dipping re~ectors are identi_ed in the
crust[ The western dipping events are interpreted as traces of thrusts with an Apenninic vergence\ the eastern dipping events are
probably extensional detachments faults[ These faults are seen deep in the crust and may be shear zone in the ductile crust[ The
extensional faults and the thrusts have been previously identi_ed on the industrial lines but these lines are processed at a depth of 3 s
TWTT and consequently the deep re~ections are not imaged[ The industrial lines and the correlations with the exploratory wells
helps to extend the results of the LISA cruise in the entire region[ pilation of all the seismic data allow us to present the _rst
depth to basement map of this region[ The major feature of the study area is the Corsica basin that is more than 7[4 km deep[ The
deep part of this huge basin is probably _lled by OligoceneÐearly Miocene deposited in an extensional regime[ However this extension
persisted during the Miocene[ The steep faults that bounds the basin toward the west are imaged and we present a model in ramp\
and ~at system\ that explains the particular geometr